From: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
Wait for the command transmission to be completed in the DSI transfer
function polling for the dc_start bit to go back to idle state after the
transmission is started.
This is documented in the datasheet and failures to do so lead to
commands corruption.
Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
---
drivers/gpu/drm/bridge/tc358768.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 0e8813278a2f..bb1750a3dab0 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -125,6 +125,9 @@
#define TC358768_DSI_CONFW_MODE_CLR (6 << 29)
#define TC358768_DSI_CONFW_ADDR_DSI_CONTROL (0x3 << 24)
+/* TC358768_DSICMD_TX (0x0600) register */
+#define TC358768_DSI_CMDTX_DC_START BIT(0)
+
static const char * const tc358768_supplies[] = {
"vddc", "vddmipi", "vddio"
};
@@ -229,6 +232,21 @@ static void tc358768_update_bits(struct tc358768_priv *priv, u32 reg, u32 mask,
tc358768_write(priv, reg, tmp);
}
+static void tc358768_dsicmd_tx(struct tc358768_priv *priv)
+{
+ u32 val;
+
+ /* start transfer */
+ tc358768_write(priv, TC358768_DSICMD_TX, TC358768_DSI_CMDTX_DC_START);
+ if (priv->error)
+ return;
+
+ /* wait transfer completion */
+ priv->error = regmap_read_poll_timeout(priv->regmap, TC358768_DSICMD_TX, val,
+ (val & TC358768_DSI_CMDTX_DC_START) == 0,
+ 100, 100000);
+}
+
static int tc358768_sw_reset(struct tc358768_priv *priv)
{
/* Assert Reset */
@@ -516,8 +534,7 @@ static ssize_t tc358768_dsi_host_transfer(struct mipi_dsi_host *host,
}
}
- /* start transfer */
- tc358768_write(priv, TC358768_DSICMD_TX, 1);
+ tc358768_dsicmd_tx(priv);
ret = tc358768_clear_error(priv);
if (ret)
--
2.39.5
